Six policemen were killed and three injured on Friday when a bomb exploded at a security checkpoint in Cairo, security sources said.
There was no immediate claim of responsibility for the attack in Al Haram street leading to the Pyramids, in which four civilians were also hurt.
The policemen were either in or close to their car when the device went off in or near a garbage can, the sources said.
The attack, close to a government building in a middle class neighbourhood of Cairo, was the latest in a series of security incidents in Egypt often claimed by radical Islamists.
Security forces killed three gunmen on Tuesday in a raid on a hideout in southern Egypt used by what they described as an armed wing of the Muslim Brotherhood, which claimed responsibility in September for an assassination attempt on a senior prosecutor.
An Egyptian general was killed by militants on Nov. 4 near his home in North Sinai in an attack for which Islamic State claimed responsibility. He was the second military officer of his rank to be shot dead in as many weeks.
Hundreds of soldiers and police have been killed in an Islamist insurgency led by Islamic State in the Sinai Peninsula.
Attacks have stepped up since the military overthrew President Mohamed Mursi of the Muslim Brotherhood, Egypt’s oldest Islamist movement, in 2013 following mass protests against him.
Judges, policemen and senior officials have been targeted by radical Islamists angered by long prison sentences imposed on members of the now-outlawed Brotherhood.